The species falls within the M. rooseveltorum complex of species. Assignment of the name to an external morphological diagnosis is problematic because the holotype is an incomplete skull (male) and therefore only those skull characters observable on this specimen are objectively known to be those of the species. Assignment of any further characters, including all relating to pelage, relies on subjective association of other specimens with the name. Although it is almost always justified to assume that a series of specimens of the same general type from the same general area do comprise one species, the confusion into which such assumptions have pitched understanding of muntjac status in Lao PDR and Viet Nam, and the apparent sympatry of two or more species within the M. rooseveltorum species-complex within this same area, urges a precautionary approach here. Caution is further indicated by results from camera-trapping in and around the type locality, which suggests on the basis of pelage features that there may be more than one species within the M. rooseveltorum species-complex in the general area (R.J. Timmins pers. comm. 2008 based on WCS unpublished data). Such sympatry would explain certain incongruities such as Rabinowitz et al. (1999) apparently having measured, from the same general area, the skulls of a slightly larger form with short premaxillae that are separated from the nasals, as well as the seemingly smaller specimens of the type series which have long premaxillae that contact the nasals (R.J. Timmins pers. comm. 2008 based on type material in ANNH, Rabinowitz et al. 1999). The premaxilla length seems to separate the two nominal species of M. rooseveltorum and M. truongsonensis in Lao PDR and Viet Nam, indicating that, since both character-states are apparently present in northern Myanmar, there may be two species there, too (R.J. Timmins pers. comm. 2008). The assumption has been made (including by the original describers) that the name M. putaoensis applies to the animals with a red pelage similar in tone to M. vaginalis, but differing in characters of the head pelage. This however needs additional research to investigate the concordance of skulls showing features of the holotype with their associated pelage characteristics (see above). Camera-trap photographs showing the external diagnostic head-pelage characters alluded to above are taken here as provisionally referring to M. putaoensis. Statements about the species' conservation status hinge on whether the skull-based name M. putaoensis conforms to this suite of pelage characters.

It is also possible that some claims of the species based solely on morphological characteristics might actually refer to M. gongshanensis which is morphologically very similar (R.J. Timmins pers. comm. 2015, see that species account).

Justification:
The Leaf Muntjac is listed as Data Deficient, since there is a lack of certainty about the species' taxonomy, distribution, natural history, population, and threats. It is known from a limited area, but its range could be much more extensive. If the species' populations are susceptible to the high levels of hunting in the region, then this species could well be severely at risk. However, if the species is like Northern Red Muntjac M. vaginalis, then it may well be able to withstand the current hunting pressure and could warrant a listing of Near Threatened or perhaps even Least Concern. No substantive new information was received for the 2015 reassessment.

The species is known only from a limited area in northern Myanmar and adjacent India. The known range is in the mountain region between the Mali Kha and Mai Kha rivers of the Hakakaborazi National Park and adjacent Naungmung area of northern Kachin state, Myanmar, south within Kachin state through the Hponkhanrazi range to the Bumpha Bum range (also known as Sumprabum), based on camera-trap data (R.J. Timmins and Than Zaw pers. comm. based on WCS unpublished data). Schaller and Rabinowitz (2004) stated there are also specimen records from the Hukaung valley and near Saramati massif, this latter extending the species' range south to 25°42′N, 95°13′E. Records of M. putaoensis from northeastern India (Datta et al. 2003) initially identified morphologically have been confirmed by recent genetic analysis of five specimens as M. putaoensis (James et al. 2008). Specimens came from the villages of Lumpang (96°10′09″E, 27°17′45″E) and of Mossang Putok (96°17′38″E, 27°20′37″E), in the general areas of the northeast part of Namdapha Tiger Reserve and reserve forests to the south-west in the Patkai hills in Jairampur Forest Division (Datta et al. 2003, James et al. 2008). Choudhury (2013) lists the species from Anjaw, Lohit, Changlang, Dibang Valley and Lower Dibang Valley districts of Arunachal Pradesh as well as several districts of Nagaland. The species could also occur east from its known range in Myanmar towards the border of China, and possibly into China, Wang (2003) listed the species, without caveat of identification for Yunnan, specifically ‘western parts-Tengchong, Lianghe, Yingjiang and Longchuan’. No details were given for the basis of this statement. During a review of muntjac specimens in the mammology collection of the Kunming Institute of Zoology in 2015 no specimens of the M. rooseveltorum species group were found (R. J. Timmins pers. comm. 2015). The southern extent of the species’ range is very uncertain as little survey work has been carried out in potentially suitable areas. Furthermore all records of the species based solely on morphological characters should be viewed with caution because of the possibility of confusion with the morphologically very similar M. gongshanensis (R.J. Timmins pers. comm. 2015, see that species Red List account).

The known elevational range based on camera-trap data is from 700 m to 1,220 m asl in Myanmar (R.J. Timmins and Than Zaw pers. comm. 2008, based on WCS unpublished data), Indian specimens were reported by hunters to have come from 900–1,100 m asl (Datta et al. 2003). Choudhury (2013) gives reported ranges of 800 – 2000 m for Arunachal Pradesh and 1,700 – 3,000 m for Nagaland, but these should be viewed with extreme caution given the potential for confusion with M. gongshanensis and potentially another muntjac species in the M. rooseveltorum group. Amato et al. (1999b) stated that the Leaf Muntjac “resides ‘on mountain tops’ while the other two larger sympatric species, the common [Northern Red] muntjac, M. muntjak, and the [a taxon allied to] black muntjac, M. crinifron are found lower down”. Rabinowitz et al. (1999) made a similar statement that the species was only found on “distant hilltops” away from village areas from 1,600 to 2,000 m asl. These statements are not consistent with more specific information from Myanmar and India, above.

There is no substantive information on the global population size or trends for this species, but camera-trapping within the species' range has captured it with similar frequency to Northern Red Muntjac, suggesting that it is likely to be naturally abundant (R.J. Timmins and Than Zaw pers. comm. 2008 based on WCS unpublished data). Sample sizes are too small to say anything more conclusive (R.J. Timmins and Than Zaw pers. comm. 2008 based on WCS unpublished data). Villagers’ assessments of hunting levels suggest that the species is relatively abundant but decreasing over time (Rabinowitz et al. 1999). Even speculative assumptions are hampered by the potential taxonomic issues, and the likelihood of misidentification both of ‘specimens’ and camera-trap images and through interpretation of local knowledge pertaining to muntjac species.

All known localities are in forest and like other muntjacs the Leaf Muntjac is probably tied to forest. There is no information available on its tolerance to degradation and fragmentation. The species occurs sympatrically with Northern Red Muntjac but is probably largely allopatric with M. gongshanensis, with the latter apparently at higher altitudes (R.J. Timmins and Than Zaw pers. comm. 2008 based on WCS unpublished data). The species apparently feeds on a range of plant materials, including fruits, an examination of stomach contents by Rabinowitz et al. (1999) revealed mostly fruit.

The major threat to Leaf Muntjac may be hunting, not targeted on this species, which is heavy throughout its Indian and Myanmar range (Datta et al. 2003, Than Zaw and J.W. Duckworth pers. comm. 2006), but the species' resilience to such hunting is unknown. The presumed Indian range is within areas of rapid habitat loss and human expansion, much of the Myanmar range is within an area which has seen remarkable stability of forest cover (Renner et al. 2007). However, this healthy situation may change in the near future, as some other forests of northern Kachin (which have not been surveyed for the species, and so may hold, or have held, it) have recently been devastated (Eames 2007). Although habitat needs, and thus the effects of forest fragmentation and degradation are essentially unknown, it is unlikely that viable populations can survive outright forest conversion. It is also likely that in areas where forest is being fragmented, negative effects of hunting on populations of Leaf Muntjac are compounded and populations decline, whatever intrinsic ability the species has to use fragmented areas.

Rabinowitz et al. (1999) suggested that this species and other muntjacs are less adaptable than other deer, and that this might explain the ‘restricted’ ranges of this and other small muntjacs. However, the most widespread muntjacs, M. muntjak, M. vaginalis, and M. reevesi, are very successful: they use a wide variety of forested habitats, and are well able to exploit secondary and degraded habitats. Secondly, and contrary to the statements of Rabinowitz et al. (1999) and others, which have not taken into account the patchiness of suitable surveying, the ‘small’ muntjacs comprising the M. rooseveltorum species-complex are not particularly restricted in range, but are rather widespread in montane areas of northern southeast Asia. The lack of evidence of the complex from many areas, giving an apparent disjunct distribution, is much more likely to reflect the paucity of suitable surveys than the genuine distribution pattern. Survey work in southwest and southeast China, much of Myanmar, the Himalayan region and northern and western Thailand have certainly been insufficient to conclude anything about the range of this species-complex in those regions.

There is limited knowledge on this newly discovered species, and more information is needed on its biology, ecology, threats, and population size and trends. The known range has several large protected areas. The major taxonomic uncertainties over this group of species needs resolution before a solid conservation assessment can be made.

Muntjac-leather jackets are an almost ubiquitous status apparel in Myitkyina and other Kachin state towns, although there is no information on the proportions of the different muntjac species used in their manufacture (J.W. Duckworth pers. comm. 2008). Even in advance of any further taxonomic understanding it can be assumed that hunting management activities are likely to be a conservation need for this muntjac; if it is a species with limited resilience to hunting, such measures are urgently needed.